Tourbillons for mechanical clocks and clockwork movements are well-known. Here, the escape wheel, the pallets and the so-called balance of the clockwork movement are carried by a mobile cage which is coupled to or has a fixed connection with the shaft of the fourth wheel, and thus to the fourth pinion. The balance or staff coincides here typically with an imaginary axis extension of the fourth pinion. A toothed wheel connected to the escape wheel finally meshes with a fixed toothed wheel coaxial with the staff so that the tourbillon, thus its cage, makes one complete revolution per minute.
For an exact setting of a mechanical watch, it is necessary to stop the indication of seconds. With conventional clockwork movements, this is made mostly by a so-called balance stop, which for example is activated by pulling out the crown and can be deactivated by pushing back the crown wheel.
Watches with a minute-tourbillon, having an indication of seconds being made by the mobile cage of the tourbillon, the implementation of such a balance stop turns out to be extremely difficult and complicated.
A balance stop for a tourbillon is well-known, for example from EP 2 793 087 A1. It is performed by a braking-element which can be brought into engagement with the staff and is movable coaxial with the latter. To match the watch with a standard time, it is therefore possible to stop the balance, and thus the tourbillon mechanism at any time.